1. Field of the Invention
A nail polish in which the conventional film former, nitrocellulose, and the conventional hardener, formaldehyle or a formaldehyde resin, are omitted and, in lieu thereof, ethyl methacrylate polymer of a low molecular weight is employed as the film former.
2. Description of the Prior Art
It has been conventional for many decades to commercially use nitrocellulose as the film former for nail polish. Many other film formers have been proposed but none has come into widespread commercial use. Nitrocellulose as a film former in nail polish has various drawbacks which have been overlooked because of the low cost of nitrocellulose. Nail polishes employing this film former have been generally accepted by the public. Such polishes have many desirable attributes such as a reasonably long life, a high gloss, and an acceptable moisture vapor transmission rate. However, unmodified nitrocellulose nail polishes tend to lift off the nail and are subject to yellowing with age in the bottle.
Furthermore, nitrocellulose is basically an explosive, namely, gun cotton, so that its manufacture and transfer prior to incorporation in the nail polish represents a hazard. There are many states in the United States which do not permit the manufacture of nitrocellulose. It would be quite advantageous to provide a nail polish that does not require nitrocellulose, thereby to limit the problems created by this potential explosive.
The incorporation of formaldehyde or formaldehyde resin in a nitrocellulose nail polish also is frowned upon because they dry the nails and make the nails brittle.
Furthermore, nitrocellulose nail polishes create allergenic problems for some of their users, and nitrocellulose tends to yellow in the bottle because of its chemical instability.
It has been proposed to use other film formers in addition to or in replacement of the nitrocellulose, but none of these suggested modifications has found its way into widespread public acceptance.
By way of example, reference is made to U.S. Pat. No. 2,173,755 which suggests the substitution of non-flammable esters of cellulose for nitrocellulose, mentioning cellulose aceto butyrate and ethyl cellulose.
U.S. Pat. No. 3,483,289 mentions the addition to nitrocellulose nail polishes of material such as cellulose acetate, methyl and ethyl cellulose, benzyl cellulose, cellulose aceto propionate, cellulose aceto butyrate, alkyds, urea formaldehyde resins, melamine, casein, zein, phenol-formaldehyde and phenol-furfural resins, vinyl-polyvinyl acetate, polyvinyl chloride, polyvinyl butyrate, vinylidine chloride, copolymers of vinyl and polyvinyl acetates and butyrates, polymethyl methacrylate, polyethylacrylate, sulfonamide-formaldehyde, maleic and maleic anhydride, and linseed oil type resins.
U.S. Pat. No. 3,927,203 discloses nail polishes containing a copolymer of at least one alkoxy alkyl acrylate or methacrylate with at least one different alkoxy alkyl acrylate or methacrylate or at least one hydroxy alkyl acrylate or methacrylate and, optionally, a minor amount of a further monomer.
U.S. Pat. No. 4,097,589 discloses a nail polish whose basic film former is nitrocellulose but which also includes a copolyamide.
U.S. Pat. No. 4,126,675 discloses a nail polish whose basic film former is nitrocellulose but which also may include acrylate copolymers of methyl methacrylate and hexyl methacrylate.
U.S. Pat. No. 4,158,053 discloses a nail polish of the water-base type in which the film former is an aqueous emulsion polymer of acrylates and methacrylates and, optionally, styrenes.
U.S. Pat. No. 4,179,304 discloses a nail polish containing nitrocellulose as the film former, formaldehyde resin as the hardener, and a mixture of sucrose esters as modifiers. Other film forming resins whose use is mentioned are cellulose propionate, cellulose acetate butyrate, ethyl cellulose, and acrylic resins which are homopolymers and copolymers of alkyl acrylates and methacrylates.
Finally, Australian Pat. No. 64,458 of 1965 discloses a nail polish which employs as the film former one or a combination of resins selected from the group consisting of polyvinyl alcohol, polyvinyl acetate, polyamide resins, acrylic resins, cyclic ketones, nitrocellulose, ethyl cellulose, methyl cellulose, and modified resin derivatives, all characterized by their solubility in alcohol, water, or low odor aliphatic or aromatic hydrocarbon solvents or blends thereof.